Testing System for the Mechanical Properties of Small-Scale Specimens Based on 3D Microscopic Digital Image...

Area of Science:

• Materials Science
• Mechanical Engineering
• Optical Measurement

Background:

• Testing mechanical properties of small specimens is challenging due to size limitations and difficulties in full-field strain measurement.
• Accurate characterization of micro-scale materials is crucial for advancements in various engineering fields.

Purpose of the Study:

• To develop and validate a novel testing system for evaluating the mechanical properties of small-scale specimens.
• To address the limitations of current methods in measuring full-field strain at the microscale.

Main Methods:

• Integration of a micro tensile machine with a three-dimensional (3D) microscopic digital image correlation (DIC) system.
• Investigation of shape function effects on the accuracy of the inverse compositional Gauss-Newton (IC-GN) algorithm.
• Application of a modified iteratively weighted radial alignment constraint method to reduce reprojection error.

Main Results:

• Numerical experiments confirmed that under-matched shape functions lead to significantly larger errors than over-matched ones.
• The modified radial alignment constraint method successfully reduced reprojection error.
• The developed system accurately measured displacement and uniaxial properties, demonstrating its capability for full-field strain analysis.

Conclusions:

• The proposed testing system effectively overcomes the challenges in characterizing small-scale material properties.
• The 3D microscopic DIC combined with a micro tensile machine provides accurate full-field strain and mechanical property measurements.
• This system offers a reliable solution for the mechanical testing of micro- and nano-scale materials.